Hong Kong has three more suspected cases of dengue fever after the family members of a 46-year-old Caucasian man confirmed with the disease tested positive for it.

This brings the total number of suspected cases to four. The Centre for Health Protection is waiting for the results of further confirmatory tests on a two-year-old girl who is a neighbour of the family and has developed symptoms.

The three family members are the man's 47-year-old wife and his sons, aged eight and 18. Their blood specimens obtained by the centre yesterday proved positive for the dengue virus. Confirmatory tests are being carried out.

The two sons developed fever early this month, while the man's wife said she had had a headache and skin rashes. Their domestic helper tested negative for the virus.

Staff from the centre yesterday visited the ESF International Kindergarten (Hillside) and Bradbury School, which the girl and the eight-year-old boy attend, and distributed questionnaires.

None of their classmates have reported symptoms. Blood tests will be arranged with parents' consent.

By yesterday, blood samples from 66 people had been taken for laboratory analysis. A spokesman said the centre was highly concerned about the cases.

With the Food and Environmental Hygiene Department, its staff will give a talk about dengue fever tomorrow afternoon at Stanley Bay Community Hall in Southern district to brief people on the means of infection, symptoms and preventive measures for the disease.

Departments have stepped up surveillance and pest control in the district. The Food and Environmental Hygiene Department yesterday sent its pest control officers to spray mosquito breeding areas in Stubbs Road and the surrounding area.

The department said the operation would take several days.

The ESF has three schools on the south side of Hong Kong Island: Kennedy School and West Island School in Pok Fu Lam, and South Island School in Shouson Hill.

An ESF spokeswoman said it had not stepped up health checks on students attending its schools, or anti-mosquito measures following the dengue fever outbreak in Deep Water Bay.

'We are awaiting advice from the Centre for Health Protection on whether any measures should be taken,' she said.

On Wednesday, the centre issued a dengue fever alert after the first locally acquired case in seven years of the potentially fatal disease involving the girl's neighbour in Island Road - the 46-year-old Caucasian man - was confirmed. More than 200 families living nearby were asked to take blood tests for the mosquito-borne disease yesterday.

Alarm signal

A dengue fever alert was issued on Wednesday after the first locally acquired case in this number of years: 7